1. Field of the Invention
The present invention relates to a microscope objective lens system and more specifically to a microscope objective lens system having large working distance.
2. Description of the Prior Art
A cover glass approximately 0.17 mm thick is used for general microscopic observations. In order to observe cells which are being cultivated in a culture dish, however, it is obliged to observe such cells through a transparent bottom 0.8 to 1.2 mm thick of said culture dish which has far larger thickness than a cover glass. Further, it is also obliged to observe the cells in such a condition that they are floating in a culture fluid. For the reasons mentioned above, an objective lens system for microscopes must have large working distance. On the other hand, chromatic aberration, spherical aberration and coma will generally tend to be aggravated in a plan objective lens system having a large working distance.